[Cogl] [PATCH v2] cogl-gst: expose aspect ratio apis
Neil Roberts
neil at linux.intel.com
Mon Apr 29 10:00:03 PDT 2013
Great, looks good to me, thanks.
It would be good to add the new functions to
doc/reference/cogl-gst/cogl-gst-sections.txt.
Reviewed-by: Neil Roberts <neil at linux.intel.com>
Regards,
- Neil
Robert Bragg <robert at sixbynine.org> writes:
> From: Robert Bragg <robert at linux.intel.com>
>
> This fixes the arithmetic precedence mistake in the last patch and also updates
> the _fit_size api to take and return a rectangle whereby the output rectangle
> can also be centered too for more convenience.
>
> This patch is now based on master instead of the cogl-gst-1.x branch
>
> -- >8 --
>
> This adds several utility apis that aim to make it as easy as possible
> for an application to determine what size a video should be drawn at.
>
> The important detail here is that these apis take into account the
> pixel-aspect-ratio in addition to the video's own aspect ratio.
>
> This patch updates the cogl-basic-video-player example to use the
> cogl_gst_video_sink_fit_size() api to perform letterboxing.
> ---
> cogl-gst/cogl-gst-video-sink.c | 57 +++++++++++++++
> cogl-gst/cogl-gst-video-sink.h | 92 ++++++++++++++++++++++++
> examples/cogl-basic-video-player.c | 139 +++++++++++++++++++++++++++++--------
> 3 files changed, 258 insertions(+), 30 deletions(-)
>
> diff --git a/cogl-gst/cogl-gst-video-sink.c b/cogl-gst/cogl-gst-video-sink.c
> index 50c2f91..1eaa82c 100644
> --- a/cogl-gst/cogl-gst-video-sink.c
> +++ b/cogl-gst/cogl-gst-video-sink.c
> @@ -1271,3 +1271,60 @@ cogl_gst_video_sink_new (CoglContext *ctx)
>
> return sink;
> }
> +
> +float
> +cogl_gst_video_sink_get_aspect (CoglGstVideoSink *vt)
> +{
> + GstVideoInfo *info = &vt->priv->info;
> + return ((float)info->width * (float)info->par_n) /
> + ((float)info->height * (float)info->par_d);
> +}
> +
> +float
> +cogl_gst_video_sink_get_width_for_height (CoglGstVideoSink *vt,
> + float height)
> +{
> + float aspect = cogl_gst_video_sink_get_aspect (vt);
> + return height * aspect;
> +}
> +
> +float
> +cogl_gst_video_sink_get_height_for_width (CoglGstVideoSink *vt,
> + float width)
> +{
> + float aspect = cogl_gst_video_sink_get_aspect (vt);
> + return width / aspect;
> +}
> +
> +void
> +cogl_gst_video_sink_fit_size (CoglGstVideoSink *vt,
> + const CoglGstRectangle *available,
> + CoglGstRectangle *output)
> +{
> + if (available->height == 0.0f)
> + {
> + output->x = available->x;
> + output->y = available->y;
> + output->width = output->height = 0;
> + }
> + else
> + {
> + float available_aspect = available->width / available->height;
> + float video_aspect = cogl_gst_video_sink_get_aspect (vt);
> +
> + if (video_aspect > available_aspect)
> + {
> + output->width = available->width;
> + output->height = available->width / video_aspect;
> + output->x = available->x;
> + output->y = available->y + (available->height - output->height) / 2;
> + }
> + else
> + {
> + output->width = available->height * video_aspect;
> + output->height = available->height;
> + output->x = available->x + (available->width - output->width) / 2;
> + output->y = available->y;
> + }
> + }
> +}
> diff --git a/cogl-gst/cogl-gst-video-sink.h b/cogl-gst/cogl-gst-video-sink.h
> index a9694a6..45ed835 100644
> --- a/cogl-gst/cogl-gst-video-sink.h
> +++ b/cogl-gst/cogl-gst-video-sink.h
> @@ -330,6 +330,98 @@ void
> cogl_gst_video_sink_setup_pipeline (CoglGstVideoSink *sink,
> CoglPipeline *pipeline);
>
> +/**
> + * cogl_gst_video_sink_get_aspect:
> + * @sink: A #CoglGstVideoSink
> + *
> + * Returns a width-for-height aspect ratio that lets you calculate a
> + * suitable width for displaying your video based on a given height by
> + * multiplying your chosen height by the returned aspect ratio.
> + *
> + * This aspect ratio is calculated based on the underlying size of the
> + * video buffers and the current pixel-aspect-ratio.
> + *
> + * Return value: a width-for-height aspect ratio
> + *
> + * Since: 1.16
> + * Stability: unstable
> + */
> +float
> +cogl_gst_video_sink_get_aspect (CoglGstVideoSink *sink);
> +
> +/**
> + * cogl_gst_video_sink_get_width_for_height:
> + * @sink: A #CoglGstVideoSink
> + * @height: A specific output @height
> + *
> + * Calculates a suitable output width for a specific output @height
> + * that will maintain the video's aspect ratio.
> + *
> + * Return value: An output width for the given output @height.
> + *
> + * Since: 1.16
> + * Stability: unstable
> + */
> +float
> +cogl_gst_video_sink_get_width_for_height (CoglGstVideoSink *sink,
> + float height);
> +
> +/**
> + * cogl_gst_video_sink_get_height_for_width:
> + * @sink: A #CoglGstVideoSink
> + * @width: A specific output @width
> + *
> + * Calculates a suitable output height for a specific output @width
> + * that will maintain the video's aspect ratio.
> + *
> + * Return value: An output height for the given output @width.
> + *
> + * Since: 1.16
> + * Stability: unstable
> + */
> +float
> +cogl_gst_video_sink_get_height_for_width (CoglGstVideoSink *sink,
> + float width);
> +
> +/**
> + * CoglGstRectangle:
> + * @x: The X coordinate of the top left of the rectangle
> + * @y: The Y coordinate of the top left of the rectangle
> + * @width: The width of the rectangle
> + * @height: The height of the rectangle
> + *
> + * Describes a rectangle that can be used for video output.
> + */
> +typedef struct _CoglGstRectangle
> +{
> + float x;
> + float y;
> + float width;
> + float height;
> +} CoglGstRectangle;
> +
> +/**
> + * cogl_gst_video_sink_fit_size:
> + * @sink: A #CoglGstVideoSink
> + * @available: The space available for video output
> + * @output: The return location for the calculated output position
> + *
> + * Calculates a suitable @output rectangle that can fit inside the
> + * @available space while maintaining the aspect ratio of the current
> + * video.
> + *
> + * Applications would typically use this api for "letterboxing" by
> + * using this api to position a video inside a fixed screen space and
> + * filling the remaining space with black borders.
> + *
> + * Since: 1.16
> + * Stability: unstable
> + */
> +void
> +cogl_gst_video_sink_fit_size (CoglGstVideoSink *sink,
> + const CoglGstRectangle *available,
> + CoglGstRectangle *output);
> +
> G_END_DECLS
>
> #endif
> diff --git a/examples/cogl-basic-video-player.c b/examples/cogl-basic-video-player.c
> index ac6bb4b..ba1e6c6 100644
> --- a/examples/cogl-basic-video-player.c
> +++ b/examples/cogl-basic-video-player.c
> @@ -1,17 +1,23 @@
> +#include <stdbool.h>
> +
> #include <cogl/cogl.h>
> #include <cogl-gst/cogl-gst.h>
>
> typedef struct _Data
> {
> CoglFramebuffer *fb;
> - CoglPipeline *pln;
> + CoglPipeline *border_pipeline;
> + CoglPipeline *video_pipeline;
> CoglGstVideoSink *sink;
> - CoglBool draw_ready;
> - CoglBool frame_ready;
> + int onscreen_width;
> + int onscreen_height;
> + CoglGstRectangle video_output;
> + bool draw_ready;
> + bool frame_ready;
> GMainLoop *main_loop;
> }Data;
>
> -static CoglBool
> +static gboolean
> _bus_watch (GstBus *bus,
> GstMessage *msg,
> void *user_data)
> @@ -57,16 +63,55 @@ _draw (Data *data)
> */
> CoglPipeline* current = cogl_gst_video_sink_get_pipeline (data->sink);
>
> - cogl_framebuffer_clear4f (data->fb,
> - COGL_BUFFER_BIT_COLOR|COGL_BUFFER_BIT_DEPTH, 0,
> - 0, 0, 1);
> - data->pln = current;
> + data->video_pipeline = current;
>
> - cogl_framebuffer_push_matrix (data->fb);
> - cogl_framebuffer_translate (data->fb, 640 / 2, 480 / 2, 0);
> - cogl_framebuffer_draw_textured_rectangle (data->fb, data->pln, -320, -240,
> - 320, 240, 0, 0, 1, 1);
> - cogl_framebuffer_pop_matrix (data->fb);
> + if (data->video_output.x)
> + {
> + int x = data->video_output.x;
> +
> + /* Letterboxed with vertical borders */
> + cogl_framebuffer_draw_rectangle (data->fb,
> + data->border_pipeline,
> + 0, 0, x, data->onscreen_height);
> + cogl_framebuffer_draw_rectangle (data->fb,
> + data->border_pipeline,
> + data->onscreen_width - x,
> + 0,
> + data->onscreen_width,
> + data->onscreen_height);
> + cogl_framebuffer_draw_rectangle (data->fb, data->video_pipeline,
> + x, 0,
> + x + data->video_output.width,
> + data->onscreen_height);
> + }
> + else if (data->video_output.y)
> + {
> + int y = data->video_output.y;
> +
> + /* Letterboxed with horizontal borders */
> + cogl_framebuffer_draw_rectangle (data->fb,
> + data->border_pipeline,
> + 0, 0, data->onscreen_width, y);
> + cogl_framebuffer_draw_rectangle (data->fb,
> + data->border_pipeline,
> + 0,
> + data->onscreen_height - y,
> + data->onscreen_width,
> + data->onscreen_height);
> + cogl_framebuffer_draw_rectangle (data->fb, data->video_pipeline,
> + 0, y,
> + data->onscreen_width,
> + y + data->video_output.height);
> +
> + }
> + else
> + {
> + cogl_framebuffer_draw_rectangle (data->fb,
> + data->video_pipeline,
> + 0, 0,
> + data->onscreen_width,
> + data->onscreen_height);
> + }
>
> cogl_onscreen_swap_buffers (COGL_ONSCREEN (data->fb));
> }
> @@ -108,6 +153,32 @@ _new_frame_cb (CoglGstVideoSink *sink,
> _check_draw (data);
> }
>
> +static void
> +_resize_callback (CoglOnscreen *onscreen,
> + int width,
> + int height,
> + void *user_data)
> +{
> + Data *data = user_data;
> + CoglGstRectangle available;
> +
> + data->onscreen_width = width;
> + data->onscreen_height = height;
> +
> + cogl_framebuffer_orthographic (data->fb, 0, 0, width, height, -1, 100);
> +
> + if (!data->video_pipeline)
> + return;
> +
> + available.x = 0;
> + available.y = 0;
> + available.width = width;
> + available.height = height;
> + cogl_gst_video_sink_fit_size (data->sink,
> + &available,
> + &data->video_output);
> +}
> +
> /*
> A callback like this should be attached to the cogl-pipeline-ready
> signal. This way requesting the cogl pipeline before its creation
> @@ -129,16 +200,26 @@ _set_up_pipeline (gpointer instance,
> */
>
> int free_layer = cogl_gst_video_sink_get_free_layer (data->sink);
> - data->pln = cogl_gst_video_sink_get_pipeline (data->sink);
> + data->video_pipeline = cogl_gst_video_sink_get_pipeline (data->sink);
>
> while (free_layer > 0)
> {
> free_layer--;
> - cogl_pipeline_set_layer_filters (data->pln, free_layer,
> + cogl_pipeline_set_layer_filters (data->video_pipeline, free_layer,
> COGL_PIPELINE_FILTER_LINEAR_MIPMAP_LINEAR,
> COGL_PIPELINE_FILTER_LINEAR);
> }
>
> + /* disable blending... */
> + cogl_pipeline_set_blend (data->video_pipeline,
> + "RGBA = ADD (SRC_COLOR, 0)", NULL);
> +
> + /* Now that we know the video size we can perform letterboxing */
> + _resize_callback (COGL_ONSCREEN (data->fb),
> + data->onscreen_width,
> + data->onscreen_height,
> + data);
> +
> cogl_onscreen_add_frame_callback (COGL_ONSCREEN (data->fb), _frame_callback,
> data, NULL);
>
> @@ -159,33 +240,31 @@ main (int argc,
> Data data;
> CoglContext *ctx;
> CoglOnscreen *onscreen;
> - CoglMatrix view;
> - float fovy, aspect, z_near, z_2d, z_far;
> GstElement *pipeline;
> GstElement *bin;
> GSource *cogl_source;
> GstBus *bus;
> char *uri;
>
> + memset (&data, 0, sizeof (Data));
> +
> /* Set the necessary cogl elements */
>
> ctx = cogl_context_new (NULL, NULL);
> +
> onscreen = cogl_onscreen_new (ctx, 640, 480);
> - data.fb = COGL_FRAMEBUFFER (onscreen);
> + cogl_onscreen_set_resizable (onscreen, TRUE);
> + cogl_onscreen_add_resize_callback (onscreen, _resize_callback, &data, NULL);
> cogl_onscreen_show (onscreen);
>
> - cogl_framebuffer_set_viewport (data.fb, 0, 0, 640, 480);
> - fovy = 60;
> - aspect = 640 / 480;
> - z_near = 0.1;
> - z_2d = 1000;
> - z_far = 2000;
> -
> - cogl_framebuffer_perspective (data.fb, fovy, aspect, z_near, z_far);
> - cogl_matrix_init_identity (&view);
> - cogl_matrix_view_2d_in_perspective (&view, fovy, aspect, z_near, z_2d,
> - 640, 480);
> - cogl_framebuffer_set_modelview_matrix (data.fb, &view);
> + data.fb = COGL_FRAMEBUFFER (onscreen);
> + cogl_framebuffer_orthographic (data.fb, 0, 0, 640, 480, -1, 100);
> +
> + data.border_pipeline = cogl_pipeline_new (ctx);
> + cogl_pipeline_set_color4f (data.border_pipeline, 0, 0, 0, 1);
> + /* disable blending */
> + cogl_pipeline_set_blend (data.border_pipeline,
> + "RGBA = ADD (SRC_COLOR, 0)", NULL);
>
> /* Intialize GStreamer */
>
> --
> 1.8.2.1
>
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